LOS ANGELES — California could join Japan, Mexico, and other earthquake-prone countries that alert residents to the approach of powerful shaking under a bill awaiting approval from Governor Jerry Brown.

The state Legislature advanced the bill that would create a warning system during Thursday’s last hours of its session. Brown has until Oct. 13 to decide.

The United States lags behind other nations in developing a public alert system, which provides several seconds of warning after a fault ruptures — enough time for trains to brake, utilities to shut off gas lines, or people to dive under a table.

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For the past several years, the US Geological Survey and universities have tested a prototype that fires off messages to about two dozen groups in the state, mostly scientists and first responders.

The biggest challenge is finding steady funding to support and maintain a statewide network. The bill does not address where funding would come from, but it can’t be built using general fund revenues. State emergency managers would have until 2016 to hash out the funding, estimated at $80 million for the first five years of operation.

Seismic warning systems are designed to detect the first shock waves from a large jolt, calculate the strength, and alert people before the slower but damaging waves spread.

The systems can’t predict quakes and are most useful during big events where it would be meaningful to warn people far away, scientists said. If the San Andreas Fault suddenly broke, people living close to the epicenter won’t receive any warning. But those living farther away would receive notice.

During the 2011 Japanese disaster, millions of people received 5 to 40 seconds of warning by notices sent to cellphones and broadcast over airwaves.